Cystathionine B-Synthase, Genotype (833 & 919)

Abbrev Code:CBSYGN   
Order Code:LAB4746Order Name:CBS, Cystathionine B-Synthase Genotype L833 + 919
Synonyms:CBS Genotype (833 & 919); Hyperhomocysteinemia
Methodology:Amplification of DNA with restriction digest
CPT Codes: 81401 x1, G0425 x1
Turnaround Time:Results are reported within 7-10 days.
Special Instructions:Include patient history relating to hyperhomocysteinemia. A signed informed consent in the patient's medical record is required; the consent should not be sent to the laboratory. The link to the Genetic Testing Consent Form is provided as a convenience for the providers and genetic counselors. Bone Marrow Transplant Patients; If a patient is the recipient of an allogeneic transplant, this test must be done on a pre-transplant sample. Contact the Molecular Diagnostics lab to see if a pre-transplant sample is available.
Associated Links:

Genetic Testing Consent Form

Collection Instructions

Optimal Volume:10 mL
Minimum\Peds Volume:5 mL
Container:Yellow (ACD, Solution A) tube available from laboratory
Alternate Containers: Purple (EDTA)
Causes for Rejection:Incorrect anticoagulated, frozen specimen, specimen more than 5 days old, clotted specimen. Patients are only tested ONCE; if duplicate sample is collected, testing is canceled, credited and original results and collection date reported. Contact 612-273-8445 with questions.
Shared samples will not be accepted unless sent to Molecular first. Contamination will occur on automated hematology analyzers. DNA extracted at non-CLIA certified (or equivalent) lab.

Processing and Shipping

Specimen Processing:Do not process whole blood. Store at room temperature.
Shipping Instructions:Ship at room temperature.
Test Performed at or Referral Lab Molecular Diagnostics  (UMMC East Bank)


Reference Range:Results are reported as "present" or "absent" for the mutations.
Use:Determination of the presence of the G919A and/or T833C mutation of the cystathionine B-synthase (CBS) gene. This mutation results in CBS deficiency which can cause an accumulation of homocysteine in plasma (hyperhomocysteinemia) and urine (homocysteinuria). Hyperhomocysteinemia has been identified as an independent risk factor in the development of premature vascular disease.

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